RAM 5500 Chassis Cab Truck 2WD L6-6.7L DSL Turbo (2008)
The blend door actuators are connected to the A/C-heater control through the vehicle electrical system by a dedicated two-wire lead and connector of the
HVAC wire harness. The blend door actuator(s) can move the blend-air door(s) in two directions. When the A/C-heater control pulls the voltage on one
side of the motor connection high and the other connection low, the blend-air door will move in one direction. When the A/C-heater control reverses the
polarity of the voltage to the motor, the blend-air door moves in the opposite direction.
When the A/C-heater control makes the voltage to both connections high or both connections low, the blend-air door stops and will not move. The
A/C-heater control uses a pulse-count positioning system to monitor the operation and relative position of the blend door actuator(s) and the blend-air
door(s). The A/C-heater control learns the blend-air door stop positions during the calibration procedure and will store a diagnostic trouble code (DTC)
for any problems it detects in the blend door actuator circuits.
The blend door actuators are diagnosed using a scan tool.
The blend door actuators cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
